Both damn good sites. I just built a pc using all parts from those 2 plus amazon. If ya check at the bottom of this page they just made several builds at different price ranges http://www.tomshardware.com/

The main thing is that everything matches. No use buying a $500 video card if the cpu sucks. Its only as fast as its weakest link. I just built a pc using the following:

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Get a decent graphics card, like a 560 or 7950. Any processor with 4 cores or better will enough to handle the current crop of games. I uses Google Shopping Search, New Egg, Tiger Direct, Pricewatch, and Amazon.

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If that's all you are planning to play on it then you could get by with an older dual core 775 socket CPU or Dual Core AMD X2 Proccessor. All you would need for a video card is an Amd 4850 or Geforce 8600 GT, if you can find one new.